1. Field of Invention
The invention relates to a therapeutically effective combination comprising 5-25% by weight of terpinen-4-ol-containing essential oils and 0.01 to 10% by weight of tannin-containing medicinal plants or extracts or tinctures thereof, which is used for the topical treatment of cutaneous and mucous membrane affections in the veterinary sector.
2. Description of Related Art
Tea tree oil is used in particular according to the invention as terpinen-4-ol-containing essential oils. It is likewise possible to use marjoram oil and maijolaine essence. Examples of tannin-containing medicinal plants used are ratanhia root (ratanhiae radix), in particular a ratanhia root extract. Particularly preferred medicinal plants are uvae ursi folium, Quercus cortex, Thea nigra, tormentillae radix, Hamamelis folium, ratanhiae radix, Hamamelis cortex, Orthosiphonis folium and Juglandis folium. Tea tree oil (Melaleucae aetheroleum) is the essential oil obtained by steam distillation from the leaves and twig tips of Melaleucae alternifolia Cheel, Melaleucae linariifolia Sm., Melaleucae dissitiflora Mueller or other species of the genus Melaleucae (Myrtaceae).
The synergistic combination according to the invention comprises 5-25% by weight, preferably 10% by weight, of terpinen-4-ol-containing essential oils, and 0.01 to 10% by weight, preferably 0.1 to 2% by weight, of tannin-containing medicinal plants or extracts or tinctures thereof, the extracts or tinctures preferably containing 0.1 to 2% by weight of the herbal drug. Ratanhia root extract is particularly preferred. Ratanhia root extract contains not less than 5% by weight of tannins expressed as pyrogallol. At these doses, the combination according to the invention shows no toxic reactions.
The tea tree oil used in particular as an ingredient in the combination according to the invention is known (see, for example, DE-A 196 23 905), and its therapeutic effect is described in many places in the literature. It contains besides at least 30% by weight of terpinen-4-ol also a maximum of 15% by weight of 1,8-cineol and, in addition, cymene, pinene, terpineol, xcex1-terpinene, limonene, xcex1-terpineol, xcex3-terpinene. The ratanhia root extracts which are also used in particular as ingredients in the combination according to the invention are likewise known, and their therapeutic effect is described in many places in the literature.
EP 0 870 507 A1 shows that preparations containing 0.02 to 5% by weight of an essential oil, and 1 to 10% by weight of an herbal extract whose content is undefined have a synergistic antimicrobial effect in vitro, no specific target organ being indicated apart from the mouth. Tea tree oil inter alia is used as essential oil in the preparation. WO 99/34811 by the same inventors shows that preparations containing 0.1 to 5% by weight of an essential oil, and 1 to 10% by weight of an herbal extract whose content is undefined display an antimycotic effect in vitro. The preparations used in some of these cases have a composition identical to the preparations described in 0 870 507 A1. It was possible to show in the more recent publication (WO 99/34811) at most an additive effect, tending to be restricted just to the essential oil, but not a synergistic effect. A fundamental problem in the use of antimycotic preparations is their lack of activity for mixed infections, which has disadvantageous consequences because most infections are mixed infections.
It is disclosed in the Deutsche Apothekerzeitung, 1995, 135, 40-48, that tea tree oil is used in dermatological and stomatological products, for example shampoos, hand and body creams and lotions. The Journal of Family Practice, vol. 38, no. 6 (June), 1994, describes the in vivo treatment of patients suffering from onychomycosis with 100% tea tree oil. In these cases it was possible to achieve only moderate success; in particular, a high rate of recurrence was recorded. In an in vivo comparison of 10% by weight tea tree oil cream with 1% by weight tolnaftate for the treatment of patients with manifestations caused by tinea pedis, however, it emerged that tea tree oil on its own has a very weak or no antimycotic effect, equivalent to that of placebo (in this connection, see Austral. J. Dermatol. 1992; 33: 145-149). In a new in vivo study, which is described in Tropical Medicine and International Health (1999; 4; 284-287), a 5% by weight tea tree oil-containing cream was compared with a cream containing 5% by weight of tea tree oil and 2% of butenafine hydrochloride in the treatment of patients suffering from onychomycosis. In this case no effect was achievable on treatment with cream containing only tea tree oil.
In summary, recent literature shows that the results of the clinical studies carried out to date with preparations containing tea tree oil are not as convincing in vivo as are the in vitro experiments described in the older literature (see, for example, Forsch. Komplementxc3xa4rmed. 2000, 7:17-20).
In addition, skin irritation and allergic reactions are frequently observed on use of skin care and cosmetic products containing tea tree oil. It has been shown in Pharmazie, 1998, 143, 26-30, that these allergic reactions and skin irritation are primarily attributable to oxidation products resulting from autoxidation of the essential oil on storage.
Concerning the tannin-containing ratanhia root extract it was known, inter alia, (see, for example, Deutsche Apotheker Zeitung 127, vol. no. 44, pages 2256-2258 of Oct. 29, 1987), that, owing to its astringent effect, the latter is able to reduce the permeability of tissues, to increase the mechanical resistance of tissues, to impede the absorbability of toxic substances, to stop capillary hemorrhages and to achieve a mild antimicrobial effect. It was also known to employ ratanhia root extracts for bacterial infections and fungal infections of the skin (see, for example, DE-A 364 04 09 of Sato Pharm. Co.). It was furthermore known that tannin-containing herbal drugs display an antioxidant effect and have radical scavenger properties.
It has now been found according to the invention that a therapeutically effective aqueous combination comprising 5 to 25% by weight of terpinen-4-ol-containing essential oils and 0.01-10% by weight of tannin-containing medicinal plants or extracts thereof has surprisingly been shown in a clinical study to achieve a synergistic effect in the area of chronic dermatitis in animals on in vivo treatment of cutaneous and mucous membrane affections, i.e. mixed infections, which results in an extremely good curative effect on topical use in the veterinary sector. On the basis of this synergistic effect, the combination according to the invention proves to have antimycotic, antibacterial, anti-inflammatory and antiviral activity for cutaneous and mucous membrane affections and can moreover be employed for wound healing. It is likewise effective for nonspecific eczema, for allergic dermatitis, for fleabite allergy, for interdigital pyoderma, lick dermatitis and skinfold pyoderma of dogs and cats. On the basis of these effects it is possible to use the combination according to the invention inter alia for the treatment of pathological signs such as, for example, itching (pruritus), reddening (erythema), erosion, of papules, pustules, weeping surfaces, pus, crusts, hair loss (alopecia), skin thickening, urticaria, scaling, hyperpigmentation and vesicles, but also of incision wounds and abrasions, viral infections, bacterial and fungal infections, of infections in the urogentital region, ulcers and furuncles, but also of allergies and other skin problems, for example those resulting by overbreeding.
Surprisingly, the synergistic therapeutic effect of the combination according to the invention also extends in particular to mixed infections of the aforementioned type. This means that the novel therapeutically effective combination according to the invention represents a surprisingly effective and welcome alternative to the antibiotics and/or cortisone therapies customary to date.
The surprisingly good in vivo effect of the combination according to the invention presumably also derives from the fact that, for example, microorganisms are attacked and killed by the ingredients of the combination through at least two points of attack, the effect having a superadditive, i.e. synergistic, onset. The antimycotic effect of the combination in vivo is likewise surprising and was not to be expected on the basis of the virtual lack of activity, discussed above, of tea tree oil on its own in vivo on treatment of tinea pedis. The surprisingly good antiviral effect of the combination according to the invention is presumably associated with a clumping and thus inactivation of viral particles.
The use for animal therapy can take place for a large number of genera with similar skin characteristics. Particularly to be emphasized in this connection are mammals such as dogs, cats and horses (so-called companion animals), feathered species such as birds and fowls, agricultural livestock such as cows, pigs and rabbits. Hairy animals are particularly important in this connection.
The combination according to the invention also shows a good effect on topical treatment of cutaneous and mucous membrane affections in humans.
The production of terpinen-4-ol-containing preparations having high storage stability is exceptionally demanding. With the preparation according to the invention it has been possible to achieve through the addition of a tannin-containing herbal extract not just a synergistic effect. It has also emerged that, for example, ratanhia extract inhibits the autooxidation of terpinen-4-ol. Thus the preparation according to the invention has exceptionally high storage stability and is moreover very well tolerated.
In a preferred embodiment, the preparation according to the invention has a high water content. An auxiliary is required to stabilize such an emulsion with a high essential oil content over a prolonged period because, otherwise, segregation of the oily and aqueous phases occurs. Such a segregation is prevented in the preparation according to the invention through addition of 5-ureidohydantoin. Topical use of the combination according to the invention can take place in all possible topical use forms, for example as emulsions, creams, ointments, gels or liquids such as, for example, oils or tinctures, which, besides the ingredients detailed above in the combination according to the invention, also contain the additions customary in pharmaceutical preparations.